Physical Sciences and Mathematics Commons^™

Iron Isotope Cosmochemistry, Kun Wang

All Theses and Dissertations (ETDs)

Iron is the most abundant element in the Earth and the 4th most abundant in the crust and mantle; Fe is involved in every stage of planetary formation and differentiation. Iron isotope ratios are robust process tracers used to understand the origin of the Solar System, planetary formation, and differentiation processes such as the moon-forming giant impact, core-mantle segregation, and crust formation. In this dissertation, I report the most complete dataset of high-precision iron isotope compositions of a wide range of extraterrestrial samples including carbonaceous, ordinary, and enstatite chondrites, aubrites, brachinites, HED meteorites: howardites, eucrites and diogenites), martian meteorites, angrites, …

Zinc Environment In Proteins: The Flexible And Reactive Core Of Hiv-1 Ncp7 And The Inhibitory Site Of Caspase-3, A. Gerard Daniel

Theses and Dissertations

Zinc is an essential cofactor of several proteins. The roles of zinc in these proteins are classified as catalytic, structural or regulatory. Zinc present in structural sites is considered to be a chemically inert, static structural element. On the contrary, previous studies on a C2H2 type zinc finger model compound and the C3H type HIV-1 NCp7 C-terminal zinc knuckle have shown that zinc at these sites can undergo coordination sphere expansion under the influence of a Pt based electrophile. The pentacoordination observed around zinc in these experiments raises an important question: are the structural zinc motifs found in the proteins …

Estimating Norms Of Commutators, Terry A. Loring, Freddy Vides

Branch Mathematics and Statistics Faculty and Staff Publications

We find estimates on the norm of a commutator of the form $[f(x),y]$ in terms of the norm of $[x,y]$, assuming that $x$ and $y$ are bounded linear operators on Hilbert space, with $x$ normal and with spectrum within the domain of $f$. In particular we discuss $\|[x^2,y]\|$ and $\|[x^{1/2},y]\|$ for $0\leq x \leq 1$. For larger values of $\delta = \|[x,y]\|$ we can rigorous calculate the best possible upper bound $\|[f(x),y]\| \leq \eta_f(\delta)$ for many $f$. In other cases we have conducted numerical experiments that strongly suggest that we have in many cases found the correct formula for the …

Formation And Analysis Of Zinc Oxide Nanoparticles And Zinc Oxide Hexagonal Prisms And Optical Analysis Of Cadmium Selenide Nanoparticles, Jared M. Hancock

Theses and Dissertations

In this dissertation, methods to synthesize ZnO are reported. First, zinc oxide nanoparticles were synthesized with small amounts of transition metal ions to create materials called dilute magnetic semiconductors (DMS). We employed a low temperature sol-gel method that produces ZnO nanoparticles of reproducible size and incorporates cobalt, nickel, and manganese ions into the nanoparticles. Conditions were controlled such that a range of amounts of Co, Ni, and Mn were incorporated. The incorporation was tracked by color changes in the white ZnO powder to blue for Co, green for Ni and yellow for Mn. XRD measurements showed the nanoparticles were on …

Multi-Scale Computational Enzymology: Enhancing Our Understanding Of Enzymatic Catalysis, Rami Gherib, Hisham Mohammed Mohammed Dokainish, James Gauld

Chemistry and Biochemistry Publications

Elucidating the origin of enzymatic catalysis stands as one the great challenges of contemporary biochemistry and biophysics. The recent emergence of computational enzymology has enhanced our atomistic-level description of biocatalysis as well the kinetic and thermodynamic properties of their mechanisms. There exists a diversity of computational methods allowing the investigation of specific enzymatic properties. Small or large density functional theory models allow the comparison of a plethora of mechanistic reactive species and divergent catalytic pathways. Molecular docking can model different substrate conformations embedded within enzyme active sites and determine those with optimal binding affinities. Molecular dynamics simulations provide insights into …

A Systems Approach To Countermeasures In Credibility Assessment Interviews, Nathan Twyman, Ryan M. Schuetzler, Jeffrey Gainer Proudfoot, Aaron Elkins

Information Systems and Quantitative Analysis Faculty Proceedings & Presentations

Countermeasures, or techniques for hiding guilt during a credibility assessment examination, have long been an important topic in cognitive psychology and criminal justice fields. With recent IS research on automated screening systems, understanding the potential for countermeasures in this new paradigm is of increasing importance. This paper reports on a large experiment examining countermeasures in an automated deception detection screening context. The effectiveness of traditional countermeasure types (mental and physical) are examined, as well as an exploratory approach of trying several countermeasures at once. The exploratory approach was tested to investigate a proposed novel systems-inspired solution to countermeasures—triangulating on deception …

Hydrochemical Investigation Of A Transient Parafluvial Zone Under Drought Conditions, Platte River, Nebraska, Audrey R. Boerner

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Shallow groundwater (0.5 m -1.2 m deep) beneath a vegetated and non-vegetated fluvial island was observed in the lower Platte River, Nebraska, USA during exceptional summer drought. Over the course of three months, sub-hourly measurements of hydraulic head, and weekly measurements of redox indicators, δ²H, δ¹⁸O, and dissolved gases were analyzed together with nitrogen and carbon species from an array of shallow piezometers in the river bed and islands. These data were compared with the same parameters collected from a 15 m-deep riparian borehole. Vertical hydraulic gradients in the island piezometers indicated the vertical component to …

A Population Model For Walleye In Nebraska Irrigation Reservoirs, Robert A. Kill

School of Natural Resources: Dissertations, Theses, and Student Research

Understanding how and why fish population size changes between years is a central theme in fisheries ecology. Fishery agencies have limited time and financial resources, thus there is a need for a quantitative way to direct the limited time and financial resources so agencies can manage fisheries more efficiently. I developed a tool for fishery managers that synthesizes common population indices and evaluated the relative importance of those indices given varying uncertainty in age-0 walleye Sander vitreus survival. Under most circumstances, I determined that resources are best utilized in reducing age-0 survival uncertainty when understanding walleye population growth. I applied …

Determining Scaphirhynchus Sturgeon Population Demographics And Dynamics: Implications For Range-Wide Management, Recovery, And Conservation, Martin J. Hamel

School of Natural Resources: Dissertations, Theses, and Student Research

Sturgeons (Acipenseridae) have experienced world-wide declines as a result of anthropogenic effects such as over-harvest, habitat degradation, altered flow regimes, and pollution. Nearly all European and Asian sturgeon species have experienced population declines and have subsequently been classified as either threatened or endangered. North American sturgeons have experienced a similar plight in that all eight native sturgeon species are listed as endangered, threatened, or of special concern. Direct linkages between North American sturgeon declines and anthropogenic effects are difficult to assess due to scale considerations, fluctuating environmental conditions, difficulty in capture, and the interaction of all these effects. To recover, …

Spatial And Temporal Participation In Recreational Fishing, Dustin R. Martin

School of Natural Resources: Dissertations, Theses, and Student Research

Buffering inland fisheries against large-scale changes in ecosystem function, climate regimes, and societal valuations of natural resources requires progressive management approaches that incorporate fish and angler dynamics at large spatial and temporal scales. Current paradigms of inland fishery management generally utilize waterbody-specific, fish-centric frameworks designed to regulate fish populations directly, and anglers indirectly, through fish stock enhancement and harvest regulation. In reality, anglers are the most manageable component of a fishery but management of anglers requires explicit consideration of their behavior (e.g., spatial and temporal patterns of participant use), which, unlike fish populations, operates at a scale larger than a …

Improving Time Structure Patterns Of Orthogonal Markov Chains And Its Consequences In Hydraulic Simulations, Juan C. Jaimes-Correa

School of Natural Resources: Dissertations, Theses, and Student Research

Rainfall¹ occurrences understood as rain events are relevant for agricultural practices because temporal distribution of rainfall highly affects yield production. A few stochastic models satisfactorily generate daily rainfall events while preserving temporal and spatial dependence among multiple sites. I evaluated an extension on the traditional Orthogonal Markov chain (TOMC) model in reproducing the temporal structure of rainfall events at multiple sites in Florida (FL), Nebraska (NE) and California (CA). In addition, a simulation of watershed runoff from rainfall events, reproduced by a single- and multi-site weather generator, was conducted. Results shows that (i) a temporal structure extended …

Deformations Associated With Rigid Algebras, M Gerstenhaber, Anthony Giaquinto

Mathematics and Statistics: Faculty Publications and Other Works

The deformations of an infinite dimensional algebra may be controlled not just by its own cohomology but by that of an associated diagram of algebras, since an infinite dimensional algebra may be absolutely rigid in the classical deformation theory for single algebras while depending essentially on some parameters. Two examples studied here, the function field of a sphere with four marked points and the first Weyl algebra, show, however, that the existence of these parameters may be made evident by the cohomology of a diagram (presheaf) of algebras constructed from the original. The Cohomology Comparison Theorem asserts, on the other …

Theoretical Tailoring Of Perforated Thin Silver Films For Surface Plasmon Resonance Affinity, Renan Gongora

HIM 1990-2015

Metallic films, in conjunction with biochemical-targeted probes, are expected to provide early diagnosis, targeted therapy and non-invasive monitoring for epidemiology applications [1-4]. The resonance wavelength peaks, both plasmonic and Wood-Rayleigh Anomalies (WRAs), in the scattering spectra are affected by the metallic architecture. As of today, much research has been devoted to extinction efficiency in the plasmonic region. However, Wood Rayleigh Anomalies (WRAs) typically occur at wavelengths associated with the periodic distance of the structures. A significant number of papers have already focused on the plasmonic region of the visible spectrum, but a less explored area of research was presented here; …

Enhancing Usability Of The Multi-Channel Analysis Of Surface Wave (Masw) Technique For Subsurface Physical Property Mapping By Incorporating Random-Array Seismic Acquisition, Prasanta Malati Yeluru

Doctoral Dissertations

Subsurface imaging is very critical to exploit subsurface resources, monitor the fluid movement in the reservoir, mapping tunnels etc. As science advances scientists and other researchers are constantly trying to develop new techniques and methods for subsurface imaging that are more effective, efficient, and are more robust under varying field conditions. The main focus of this research is one such effort to improve and increase the usability of the Multi-channel Analysis of Surface Wave method (MASW) method in determining regolith and rock properties by introducing a new type of receiver arrangement to extend its usage in places that are inaccessible …

Analysis, Prototyping, And Design Of An Ionization Profile Monitor For The Spallation Neutron Source Accumulator Ring, Dirk A. Bartkoski

Doctoral Dissertations

The Spallation Neutron Source (SNS) located in the Oak Ridge National Laboratory is comprised of a 1 GeV linear H^- [H^-] accelerator followed by an accumulator ring that delivers high intensity 1 μs [microsecond] long pulses of 1.5x10¹⁴ [1.5x10^14] protons to a liquid mercury target for neutron production by spallation reaction. With its strict 0.01% total beam loss condition, planned power upgrade, and proposed second target station, SNS ring beam-profile diagnostics capable of monitoring evolving beam conditions during high-power conditions are crucial for efficient operation and improvement. By subjecting ionized electrons created during beam interactions with the residual …

Tracking Real-Time Nanoparticle Positions And Measuring Three-Dimensional Solution Flow With A Four-Focus Confocal Microscope, James Andrew Germann

Doctoral Dissertations

This dissertation presents the development of instrumentation for measuring the position of a single emitter within the sample volume of a confocal fluorescence microscope with sub-diffraction limited precision in three dimensions together with applications for determining solution flow and for tracking a fluorescent nanoparticle as it undergoes Brownian diffusion. The localization method is based on comparing photon counts from alternating excitation of the emitter by four laser beams, which are focused at slightly offset positions in a tetrahedral pattern within the confocal volume. Two experimental set-ups are constructed. In the first, the four beams are from a femtosecond laser, which …

Syntheses And Reactions Of Early Transition Metal Amidinate Compounds, Adam Christopher Lamb

Doctoral Dissertations

Homoleptic Groups 4 and 5 metal amide compounds have been used as precursors in CVD/ALD processes to make microelectronic metal oxide thin films. These compounds are often very air sensitive. Ancillary ligands such as amidinates have been used to reduce their air sensitivity and to make their handling easier. Reactions of amidinates with dioxygen and water have thus been used to make metal oxide thin films. Studies of these reactions are important in order to make better precursors and purer thin films. This dissertation focuses on the following areas: (a) Syntheses of zirconium and Group 5 amidinate amides; (b) Studies …

Numerical Study Of Hubbard Model For Iron-Based Superconductors, Qinlong Luo

Doctoral Dissertations

This thesis addresses the numerical and analytical study of the iron-based superconductors, mainly using the multi-orbital Hubbard model and Hartree-Fock approximation. The text starts with an introduction to the new iron-based superconductors, followed by a theoretical description of the multi-orbital Hubbard model and Hartree-Fock approximations. The numerical study of the Hubbard model in momentum space is described next, where the phase diagrams for three- and five-orbital Hubbard models are provided. The physically ``realistic" regime of couplings is highlighted, to guide future theoretical work into the proper region of parameters of Hubbard models for iron-based superconductors. What goes next is the …

Species Discrimination, Systematics, And Ontogeny Of Blastoidea, James William Atwood

Doctoral Dissertations

Blastoids are ideal model organisms with which to study evolutionary processes because nearly all of the skeletal elements are shared among all taxa, there have been recent advances in the understanding of blastoid homology, and they are more commonly preserved fully inflated than any other blastozoan. Because of this homology and preservation, blastoids are the perfect candidate for studies involving geometric morphometrics and systematics. But the potential of blastoids to be a model clade has been extremely hampered by the lack of a modern phylogenetics and classification.

The focus of this dissertation is to increase our understanding of blastoid species …

Geologic Investigations In The Central Georgia Inner Piedmont And The Western Flank Of The Carolina Superterrane: Implications Regarding Acadian And Alleghanian Collisional Orogenesis, Fault Reactivation, And The Mesozoic Breakup Of Pangea, Matthew Tiesher Huebner

Doctoral Dissertations

Detailed geologic mapping, U-Pb geochronology, igneous petrology and whole-rock geochemical analysis, and structural analysis of the Inner Piedmont and Carolina superterrane were conducted to better define the tectonic history of the southern Appalachian orogen; results yield implications for Acadian/Neoacadian and Alleghanian collisional events and Mesozoic breakup of Pangea. Detailed geologic mapping was focused in the Inner Piedmont at the northeastern end of the Pine Mountain window to investigate an aeromagnetic anomaly that was hypothesized to represent the southwestern continuation of the Brindle Creek fault, which separates the Inner Piedmont terranes (Tugaloo and Cat Square). Evidence supports this hypothesis, while contrasting …

A Holographic Model Of Striped Superconductors, Suman Ganguli

Doctoral Dissertations

One of the most prominent distinguishing features in strongly correlated electron systems, such as the high Tc (critical temperature) cuprates and the most recent iron pnictides, is the presence of "competing orders" that are related to the breaking of the lattice symmetries. Does the ubiquitous presence of such inhomogeneous orders in strongly correlated superconductors have a deep connection to superconductivity? The answer to this question is crucial for identifying the mechanism of superconductivity, at least in the cuprates. Amidst serious difficulties within conventional theoretical framework to deal with strongly interacting degrees of freedom at finite density, "AdS/CFT correspondence" or "gauge/gravity …

Design And Synthesis Of Novel Sultams As Non-Nucleoside Inhibitors Of Hiv Reverse Transcriptase, Brian Chadwick Lecroix

Doctoral Dissertations

The compound 2-methyl-3-phenyl-2,3-dihydro-1,2-benzisothiazole 1,1-dioxide (NSC 108406) was identified as an HIV-1 reverse transcriptase inhibitor by the National Cancer Institute. Using this lead, the Baker group has developed a series of analogues with various groups at the 3-position that show a spectrum of biological activities. In the end, the substituents used could not compare to the biological activity of the inhibitor efavirenz (Sustiva^® [trademark]), and so it was decided to synthesize sultams with alkylethynyl substituents at the 3-position of the sultams in an attempt to mimic the activity of efavirenz.

Previous research analyzed the proposed novel sultams in the modeling …

Synthesis And Characterization Of Fullerene-Based Hydrogen Storage Materials, Patrick Alan Ward

Doctoral Dissertations

Storing hydrogen safely and efficiently is an area of great interest for the utilization of hydrogen as an energy carrier in transportation applications. The feasibility of using fullerenes in hydrogen storage materials was investigated. Alkali decorated fullerenes Li_xC₆₀ [LixC60] and Na_xC₆₀ [NaxC60] were found to enhance the hydrogen chemisorption and physisorption properties of fullerenes. Although the overall hydrogen physisorption uptake in these materials is low due to the crystalline nature of the material, the isosteric heats of adsorption of fullerenes were increased by lithium doping. C₆₀ [C60] is also capable of acting as …

Measurement Of The Prompt Double J/Psi Production Cross Section In Pp Collisions At Sqrt(S) = 7 Tev, Andrew David York

Doctoral Dissertations

The simultaneous production of two J/psi mesons has been significantly observed in proton-proton collisions at a center-of-mass energy of 7 TeV with the CMS detector. The two J/psi mesons are fully reconstructed in their decay to muons. The signal yield is extracted with an extended maximum likelihood fit based on four event variables. A method was developed to correct for detector acceptances and efficiencies based on the measured momenta of the J/psi and their decay muons to maintain the least model dependence possible.

The measurement is performed in an acceptance region defined by the individual J/psi transverse momentum and rapidity. …

Bayesian Dictionary Learning For Single And Coupled Feature Spaces, Li He

Doctoral Dissertations

Over-complete bases offer the flexibility to represent much wider range of signals with more elementary basis atoms than signal dimension. The use of over-complete dictionaries for sparse representation has been a new trend recently and has increasingly become recognized as providing high performance for applications such as denoise, image super-resolution, inpaiting, compression, blind source separation and linear unmixing. This dissertation studies the dictionary learning for single or coupled feature spaces and its application in image restoration tasks. A Bayesian strategy using a beta process prior is applied to solve both problems.

Firstly, we illustrate how to generalize the existing beta …

Magneto-Optical Properties Of Complex Oxides, Peng Chen

Doctoral Dissertations

Complex oxides give rise to rich physics and exotic cross-coupled electronic and magnetic properties. This is because of the competing interaction between charge, structure, and magnetism in the materials. In this dissertation I present a spectroscopic investigation of several model complex oxides under external stimuli of magnetic field and temperature. The compounds of interest include BiFeO₃ [bismuth ferrite] nanoparticles and tetragonal film, Bi_1-xNd_xFeO₃ [neodymium doped bismuth ferrite], α-Fe₂O₃ [hematite], Ni₃V₂O₈ [nickel vanadate], and RIn_1-xMn_xO₃ [manganese doped rare earth indium oxide]. …

Reaching The Gold Standard: Assessing Driving Ability Among Student And Expert Drivers, Alyssa Davis

Statistics

No abstract provided.

Common Core 4th Grade Environmental Science Lesson Plans For California Teachers, Gillian Schoenfeld

Natural Resources Management and Environmental Sciences

This project and its analyses were conducted to assist California fourth grade elementary school teachers in adjusting to teaching Common Core standards and science curriculum in their classrooms. The project included the creation of lesson plans, which could be utilized throughout the state of California.

As the Common Core standards, California’s Next Generation Science Standards for K- 12, were just proposed in June of 2013, these lesson plans would help teachers update their lessons and provide them materials and concepts of how to do so. These lessons provide higher-order thinking for students, which is the whole concept of the new …

Geoelectrical Detection Of Water Table Depth At Two Locations In The Los Osos Groundwater Basin, Hallie A. Douglas

Natural Resources Management and Environmental Sciences

The city of Los Osos sits on top of a coastal groundwater aquifer which is the sole supplier of all its residential, agricultural, and industrial water needs. Lacking a sewer system, the upper aquifer became progressively contaminated with nitrates over several decades. Groundwater pumping eventually shifted to the lower aquifer, however seawater intrusion of the lower aquifer caused by over-pumping has further degraded water quality. The Los Osos groundwater basin provides an excellent field region to examine the utility of geophysical methods for characterizing aquifer structure. In this study shallow (<20 >m) electrical resistivity imaging methods were performed at two …

Surficial Geologic Map Of Kings Canyon: Implications For Relatively Slow Stream Incision Rates, Andrew Farris

Natural Resources Management and Environmental Sciences

Most of the Kings River in the Sierra Nevada Mountains of California has responded to regional uplift with rapid incision, creating the deepest canyon in the United States. However, Kings Canyon near Cedar Grove is still a mountainous relict landscape with little evidence of fluvial incision. Mapping took place in the Cedar Grove area of Kings Canyon to assess factors and/or processes causing relatively low stream incision rates in the region during Holocene time. A surficial geologic map was created in the field, along with visual observations of the South Fork of the Kings River and characterization of geologic map …